Electric Car Battery Degradation Study Suggests Batteries Will Outlast Cars

Our knowledge on how to make batteries better continues to improve and the result is that we are finding that EV batteries can and do last longer than we thought if treated well.

The Taking Charge report from Geotab on battery degradation had some rather interesting results. Using a population of 10,000 EVs operating in North America and Europe, they found batteries degraded an average of 1.8% per year, with some degrading less than 1% per year (and Teslas tended to perform better than most).

Batteries don’t like heat and fast charging, and hot climates do contribute to higher battery degradation. However, those of us who live in cooler climates and mostly charge using Level 2 chargers in our garages will likely see the least degradation over time. That means after 20 years, or far longer than most of us keep our cars, the batteries will still have most of their capacity. 

This study also indicated that fleet managers could save around $16K per year per vehicle by switching to electric vehicles from gas.

Impact

One of the biggest concerns right now with electric vehicles is battery degradation. The cost of a new propulsion battery can exceed the value of a used EV, so swapping out the battery outside of warranty isn’t currently viable. However, battery costs have been dropping sharply over time, and battery formulations are improving the life, capability, and ability of batteries to charge more quickly while increasing energy density and range.

This study suggests that concerns about prematurely drained batteries are unfounded outside of hot climates and high usage of Level 3 superchargers. It also implies that the use of solid-state batteries and ultra-capacitors coupled with more advanced technologies to cool the batteries more effectively could make EV battery replacement as uncommon as engine replacement. It would still happen occasionally but wouldn’t be something the average driver would necessarily ever have to do outside of an accident.

In addition, this 20-year useful life, when cars, on average, only have a 12-year useful life, suggests a significant opportunity for battery refurbishment and reuse for home or business energy storage. Particularly for battery backup, which has little charging load, these refurbished batteries could last indefinitely and wouldn’t be replaced for wear but because a newer technology worked more reliably or was cheaper to maintain.

Finally, as battery capacity increases, the need to fast charge batteries decreases, allowing more people to rely on their home chargers. This, too, would extend the life of batteries and reduce both battery range and degradation anxiety.

Battery Degradation Can Be Further Reduced

A recent discovery highlighted in the Journal of Science using molecular analysis of existing lithium-ion batteries resulting from a study on reducing cobalt found that hydrogen could significantly degrade batteries over time. 

Mitigating this hydrogen contamination, which occurs now during charging, could significantly increase the useful life of existing lithium-ion batteries. When understood and applied to battery manufacturing, this study's results could increase range, lower production costs, and increase battery lifespan.

Wrapping Up:

While we are still suffering from the decades where we did little or no battery research, the speed of battery advancement continues to increase, and the more we learn, the more progress appears to be made across several related fronts. From these studies, which showcase how to make existing battery technology far better than it is today- to work on solid-state batteries and ultra-capacitors, the problems associated with current EVs, some of which appear to be more imagined than real (early battery degradation, for instance), will be mitigated or eliminated, making the future of EVs and their ability to displace ICE cars far more sure over time. 

Rob Enderle is a technology analyst at Torque News who covers automotive technology and battery development. You can learn more about Rob on Wikipedia and follow his articles on Forbes, X, and LinkedIn.